The present invention relates generally to closure mechanisms for polymer packages, for example, plastic bags. In particular, the present invention relates to leak proof resealable closure mechanisms for resealable bags.
Many packaging applications use resealable containers to store various types of articles and materials. These packages may be used to store and ship food products, non-food consumer goods, medical supplies, waste materials, and many other articles. Resealable packages are convenient in that they can be closed and resealed after the initial opening to preserve the enclosed contents. The need to locate a storage container for the unused portion of the products in the package is thus avoided. As such, providing products in resealable packages appreciably enhances the marketability of those products.
Resealable packages typically utilize a closure mechanism that is positioned along the mouth of the package. The closure mechanism often comprises profile elements or closure profiles that engage one another when pressed together. Some types of resealable packages are opened and closed using a slider device. The slider device design includes a separator or plow-type structure at one end that causes the closure mechanism to disengage when the slider device travels in a first direction along the mechanism. The side walls of the slider device are inwardly tapered from one end to the opposite end so that the side walls engage the closure profiles and progressively move them into engagement when the slider device is moved along the closure mechanism in a direction opposite the first direction, thereby closing the closure mechanism. Side seals at each end of the closure mechanism keep the slider device from sliding off the package in either direction.
While the use of a slider is convenient in terms of opening and closing the package, the presence of the separator or plow can cause problems in the sealability of the package. The separator or plow can inhibit full engagement of the closure profiles, leading to the possibility of product escaping from the package. This is a significant concern when the product is a liquid or a small solid that can leak through even the smallest opening in the package. It is therefore desirable to provide a slider and closure mechanism that can be fully sealed to prevent product leakage.
In an embodiment of the present invention, a closure mechanism is provided including first and second closure profiles, the first closure profile having first and second base strips with first and second interlocking closure members extending from the first and second base strips, respectively, and the second closure profile having third and fourth base strips with third and fourth interlocking closure members extending from the third and fourth base strips, respectively. The first and second interlocking closure members and third and fourth interlocking closure members extend a length from the first, second, third and fourth base strips sufficient for the first and third interlocking closure members and the second and fourth interlocking closure members to selectively engage. The closure mechanism further includes a slider device having first and second walls and a top that define a first cavity for receiving the first and second closure profiles. The slider device is arranged and configured to slide along the first and second closure profiles in a first direction to cause the first and second closure profiles to engage and to slide along the first and second closure profiles in a second direction to cause the first and second closure profiles to disengage. The slider device further comprises a plow. The plow comprises a substantially vertical member depending from the top of the slider and a substantially horizontal member that is connected to the substantially vertical member and is disposed between the first and third interlocking closure members and the second and fourth interlocking closure members, respectively.
In another embodiment of the present invention, a resealable package includes first and second panel sections joined together to define an enclosed region, first and second opposite side edges, a bottom edge, and a mouth that provides access to the enclosed region. The resealable package also includes a closure mechanism for selectively opening and sealing the mouth. The closure mechanism preferably includes structure as previously described herein.